This invention relates generally to the field of skylights and more particularly to self-flashing skylights designed for installation on a downwardly sloped roof.
In the field of skylight design and construction numerous configurations have been developed and utilized. These configurations have taken many shapes, although the square or rectangular shape is most common due to ease of installation provided between roof joists. Among the most common types are those having a flat or convexly curved light-transmissive portion of clear or translucent material, such as glass or synthetic resin. Most commonly these light-transmissive portions are mounted within a framework of wood or metal that is then mounted to the roof of the building involved. Some of these prior art units have been "self-flashing" in that the structure of the skylight unit itself includes flanges over which is laid the roofing material to provide a more waterproof joint between the skylight and the roof. However, even the self-flashing structures have frequently experienced leakage, particularly where a light-transmissive portion is convexly curved, because rain water is deflected around the edges of the skylight, toward the very edges where the joints between the skylight and the roof may permit such leakage. This problem frequently is especially bad where the bottom of the skylight joins the roof, since water running over the skylight may thereby be directed under the roofing material.